The understandable notes-Acid, Base and Salts, Class 10, Part -3
pH of Salts
Salts formed from a strong acid and a strong base are neutral, meaning their pH is close to 7.
Salts formed from a strong acid and a weak base will have a pH less than 7, making them acidic.
Salts formed from a strong base and a weak acid will have a pH greater than 7, making them basic.
This indicates that the nature of a salt (acidic, basic, or neutral) depends on the strength of its acid and base reactants.
( Ab salts ki formation hoti hai jab acid or base aapas mai react krte hai. Ab agar dono acid bhi aur base bhi strong ho to salt neutral banega. Agar dono hi weak ho tab bhi salt neutral hoga. Ye to common sense ki baat hai. Ab jo strong hoga chahe fir wo acid ho ta base ho salt uske jaisa hi ho jayega. Ab agar acid strong to pH kam hoga aur agar base strong hoga to pH 7 se jyada hoga. Ab is se ye bhi samajh aa jata hai ki salt ka nature reactants par depend krta hai.)
SODIUM CHLORIDE
When sodium hydroxide reacts with hydrochloric acid, it forms sodium chloride. This is a neutral salt and is used for many purposes.
This is the same salt that you use in food. Seawater contains many dissolved salts, and sodium chloride is separated from them. Deposits of solid salt are also found in several parts of the world. These large crystals are often brown due to impurities and are called rock salt. Beds of rock salt were formed when ancient seas dried up. Rock salt is mined like coal and is used as a raw material for producing many other salts.
( Tata namak desh ka namak. Iski jagah agar tata sodium chloride likha aa jaye to aadhe log to wahi chakkar kha jaye. Ab dekhte hai ki ye banta kaise hai. To sodium chloride tab banta hai jab sodium hydroxide aur hydrochloric acid aapas mai react krte hai. Ab ye dekho ki dono hi strong acid or base hai to as a result jo salt form hoga vo neutral hoga. Ab ise common dalt bhi kaha jata hai kyonki yehi wo salt hai jise hum food mai use krte hai. Ab ye to maximum bacho ko pata hi hoga ki ye salt sea water se extract kiya jata hai. Kaise kiya jata hai ye padhna ki kya jarurat hai par mai bata deta hu ki chambers banaye jate hai jisme sea water ko daalkar chod diya jata hai aur for wo sea water sun ki light ki wajah se dhire dhire evaporate ho jata hai aur last mai sara pani evaporate ho jata hai aur bas salt bachta hai. Abhi ye jo salt bacha hai ye pure namak nahi hai ise aage purify wagera kiya jata hai. Ab isi salt ke deposit earth ke andar bhi ban jate hai jaha pehle lake wagera hote honge aur baad mai dry ho gaye honge. Use rock salt ya fir sendha namak bhi bolte hai jise hum log vrat mai use krte hai. Ise mine kra jata hai jaise coal ko kiya jata hai. Baki iske fayde apni mummy se puch lena vo mere se jyada ache se samjha denge. Ab ye jo sodium chloride hai ise khane ke alawa dusre salts ke liye ek raw material ki tarah bhi use kiya jata hai. Ab jo jo salt aage padhenge unka method of preparation aur uses padh lena kyonki paper mai aane ke chances hote hai. Aur koi mere de ye mat puchna ki konsa topic important hai. Mera manna ye hai ki aapne jo sikha vo jyada important hai rather than marks. To padho to knowledge ke liye na ki marks ke liye.)
SODIUM HYDROXIDE
Sodium hydroxide is a strong base that is prepared by the electrolysis of an aqueous solution of common salt (brine). During electrolysis, salt dissociates into Na⁺ and Cl⁻ ions, while water breaks down to form hydrogen ions (H⁺) and hydroxide ions (OH⁻). These hydroxide ions bond with sodium cations to form sodium hydroxide (NaOH).
This process is called the chlor-alkali process because of the products formed—"chlor" for chlorine (Cl₂) and "alkali" for sodium hydroxide (NaOH). The chemical reaction for this process is given below:
(Ab pure chapter mai ye to pata chal hi gaya hoga ki sodium hydroxide ek strong base hai. To iske uses padhne se pehle jaruri hai iska method of preparation padhna. Ab aage jo bataunga ise dhyan se padhna. Dekho namak ko paani mai daalkar ek solution hota hai jise brine bolte hai. Ab ye to sabko pata hai ki pure water bijli conduct nahi krta but jab hum us pani mai salt add kr denge to bijli conduct hone lagegi. To ek process hota hai electrolysis jise padhne ki koi bhi jarurat nahi hai aur abhi to kahi se bhi na padhna kyonki ye class 12 ka topic hai padhoge to samajh nahi aaega aur time waste hoga wo alag. Bas abhi ke liye itna samajh lo ki jab hum electricity ka use krke compound ko break down krte hai to use electrolysis bolte hai. Ab is reaction mai salt aur water dono break down honge par bond sirf hydroxide ion or sodium ke beech mai banega. Ab kuch bache jo sach mai padh rahe wo ye soch rhe honge ki fir hydrogen aur chlorine ke beech mai to banna chahiye tha. To aisa hota nahi hai. Ye dono hi gas ki form mai emit ho jate hai. Ab ise kaise yaad rakhoge wo tumhari sirdardi hai meri nhi. Maine bata diya ki abhi tumhe ye chiz samajh hi nahi aaegi. Tumhe bas reaction aur process name yaad hona chahiye. Chemistry mai aap har chiz samajh nahi sakte to yaad krne ki aadat daal lo.)
USES OF SODIUM HYDROXIDE
1. Soap Making – Used to make soaps and detergents.
2. Paper Making – Helps in producing paper from wood.
3. Drain Cleaning – Used in cleaners to remove blockages.
(Ab inme to kuch samjhane ki jarurat nahi hai na. Fir bhi last wale mai grease breakdown ki baat ho rahi hai.Yani ki jo pipe wagera mai clot nahi jam hate use saaf krne mai bhi ska use hota hai.)
Bleaching powder
Bleaching powder is prepared by the action of chlorine gas on slaked lime (calcium hydroxide). It is represented as Ca(OCl)₂ and is also known as calcium oxychloride.
The reaction is given below
USES OF BLEACHING POWDER
(i) for bleaching cotton and linen in the textile industry, for bleaching wood pulp in paper factories and for bleaching washed clothes
in laundry;
(ii) as an oxidising agent in many chemical industries; and
(iii) to make drinking water free from germs.
( Ab aap kahoge ki NaOH bhi paper banane ke kaam aa raha tha aur ye bhi. To inka use alag alag hai. Bleaching powder paper ko white krne ke kaam aata hai. Aur ise oxidising agent, ye kya hota hai, jo dusro ko oxygen supply kre, ki tarah bhi kaam krta hai.)
BAKING SODA
Sodium bicarbonate (NaHCO₃), or baking soda, is one of the most commonly used compounds in daily life. It is prepared using common salt (NaCl), water (H₂O), carbon dioxide (CO₂), and ammonia (NH₃). The following reaction takes place:
( Jo dukan par jaakr meetha soda maangte ho na ha wahi wala usi ki baat ho rahi hai. Banta kaise hai yo to yaad rakhna padega baki uses dekh lete hai. )
Uses
(i) For making baking powder, which is a mixture of baking soda (sodium hydrogencarbonate) and a mild edible acid such as tartaric acid. When baking powder is heated or mixed in water, the following reaction takes place –
Carbon dioxide produced during the reaction can cause bread or cake to rise making them soft and spongy.
( Ab baking powder or baking soda alag alag chiz hoti hai. Baking soda ek basic salt hai jo nature mai non corrosive hota hai. Non corrosive ka matlab simple bhasha mai harmless hai. Ab iska reactio jab kisi edible acid se krate hai tab form hota hai baking powder. Ab CO2 aur H20 bhi form hoti hai aur yehi jo CO2 form hui hai ye cake, dhokla, bread wagera ko fluppy or soft banati hai. Asal mai hum carbon dioxide ko carbonated drinks mai bhi peete hai kyunki carbon to hmari body ke liye bahut jyada jaruri hai.)
(ii) Sodium hydrogencarbonate is also an ingredient in antacids. Being alkaline, it neutralises excess acid in the stomach and
provides relief.
( Ye tu maine abhi bataya hai ki ye ek basuc salt hai to iska use hum acidity wagera mai to kar hi sakte hai. Kaise eno lekar usme ye hi hota hai.)
(iii) It is also used in soda-acid fire extinguishers.
WASHING SODA
When baking soda (NaHCO₃) is heated, it decomposes to form sodium carbonate (Na₂CO₃), along with water (H₂O) and carbon dioxide (CO₂) gas. This sodium carbonate is then reacted with 10 molecules of water to form washing soda (Na₂CO₃·10H₂O).
Uses
(i) Sodium carbonate (washing soda) is used in glass, soap and paper industries.
(ii) It is used in the manufacture of sodium compounds such as borax.
(iii) Sodium carbonate can be used as a cleaning agent for domestic purposes.
(iv) It is used for removing permanent hardness of water.
( Ek hi jagah sare samjha deta hu. To dekho iska use paper wagera mai bhi hota hai. Ab sodium salt hai to sodium compound banane mai bhi jo jayega. Aur naam mai hi washing hai to cleansing agent ki tarah bhi krta hai aur ek last pani ki hardness ko remove kr sakta hai. Ab pani hard hone ka matlab hai kuch specific minerals jyada amount mai present hona.)
Are the crystals of salt dry
In simple words, no. Many salts contain a fixed amount of water molecules in them. For example:
Washing soda (Na₂CO₃·10H₂O) contains 10 water molecules.
Ferrous sulfate (FeSO₄·7H₂O) contains 7 water molecules.
Copper sulfate (CuSO₄·5H₂O) contains 5 water molecules.
These are called hydrated salts because they contain water of crystallization.
( Yaar dekho thodi bhi english aati hongi to samajh aa jayega ki upar kya likha hai. Fir bhi bata deta hu ki kuch salts ke andar water molecules present hote hai. Aap inhe touch krke feel nahi kr paoge. Human body mai 70 % pani hota hi par kabhi aisa to nahi hota hoga ki kisi to touch kra to hath uske andar hi chala gaya jaise pani mai jata hai. Baki ye do teen example hai inme se question aa sakte hai.)
Plaster of Paris
It is derived from gypsum (CaSO₄·2H₂O). On heating, it loses water molecules and becomes calcium sulfate hemihydrate (CaSO₄·½H₂O). Two moles of calcium sulfate use one mole of water, which is why it is called a hemihydrate.
( Ab last salt or chapter khatam. To POP ha wahi jo tumhare gharo mai ho rakhi hai, vo khud gypsum se banti hai. Jab gypsum ko heat kiya jata hai tab vo 1 5 mole water ke loose kr deta hai aur fir banta hai plaster of paris. Ab mai iske use bas likh dunga samjhane ki to koi jarurat nahi hai na.)
Uses
1. Making statues and decorative items – Used for making sculptures, idols, and ceiling designs.
2. Medical applications – Used for making casts to set broken bones.
3. Construction – Used for coating walls and making false ceilings.
Some common salt, acid and base to remember
Shubh ratri
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